Air Conditioning Flashcards
Each air conditioning pack are supplied pressurized and flow-regulated air by…
APU bleed.
a Ram Air Turbine (RAT).
two dedicated electric cabin air compressors (CACs).
engine or APU bleed.
two dedicated electric cabin air compressors (CACs).
Outside air is supplied to four electric cabin air compressors (CAC) through two dedicated inlets located in the wing to body fairings. The air is then pressurized and flow-regulated by the CACs and supplied to _____ air conditioning pack(s).
two identical
three identical
four identical
one
two identical
Normally, to maximize system efficiency, how many cabin air compressors (CACs) run when using the APU as the power source?
One on the left side.
Two on the right side.
One on each side.
All four.
One on each side.
A ground source of conditioned air may be used to supply conditioned air directly to the cabin distribution system, eliminating the need for pack operation.
True
False
True
If an overheat or significant pack fault is detected, the pack…
switches to standby mode.
continues to run until it is manually shut down.
switches to alternate cooling.
shuts down automatically and the EICAS advisory message PACK (L,R) is displayed.
shuts down automatically and the EICAS advisory message PACK (L,R) is displayed.
Cabin attendants can reduce outside airflow to the cabin based on…
the number of airplane occupants.
inside air temperature.
outside air temperature.
the setting of the CABIN TEMP on the flight deck air conditioning panel.
the number of airplane occupants.
Pack outlet temperature is controlled by the…
temperature zone requiring the warmest air.
trim air valve.
temperature zone requiring the coolest air.
pack valve controller
temperature zone requiring the coolest air.
What is the status of CACs and Packs during a normal engine start?
One CAC operates on each side. Both packs are commanded off.
Both CACs operate on each side. Both packs are commanded off.
All CACs are commanded off during the initial start sequence. Packs do not restart until at least two minutes after engine start sequence is initiated and engine is running.
All four CACs and both packs are fully operative during normal engine start.
All CACs are commanded off during the initial start sequence. Packs do not restart until at least two minutes after engine start sequence is initiated and engine is running.
Which of the following occurs during Standby Cooling Mode?
EICAS advisory message PACK MODE (L,R) is displayed.
STBY COOLING is displayed in amber on AIR synoptic.
Pack cooling capacity may be less than in normal mode.
All of the above are correct.
All of the above are correct.
Which of the following statements is correct when the right pack is operating in the standby cooling mode (left pack operating normally)?
The right pack automatically switches to high flow.
The right pack may shut down at higher altitudes.
The right pack cooling capacity may be less than in normal mode resulting in warm flight deck or cabin temperatures at lower altitudes.
There is no EICAS indication of either pack operating in the standby mode.
The right pack cooling capacity may be less than in normal mode resulting in warm flight deck or cabin temperatures at lower altitudes.
What cools the large motor power distribution system located in the aft E/E equipment compartment?
The Power Electronics Cooling System (PECS)
The Integrated Cooling System (ICS).
Conditioned air ducted from the passenger cabin.
The Miscellaneous Cooling System.
The Power Electronics Cooling System (PECS)
The Power Electronics Cooling System (PECS) is a liquid cooling system used to cool the large motor power distribution system. The large motor power distribution system is located in…
the aft E/E equipment compartment.
the wing to body fairings.
the temperature control compartment.
the Flight Deck equipment compartment.
the aft E/E equipment compartment.
Identify which statement about the operation of the pressurization system description is true.
In operation with the loss of pressurization, it is important that the flight crew close the outflow valves during descent.
In normal operation of the cruise mode, maximum cabin altitude is no more than 6000 feet.
Two seconds after touchdown, both outflow valves open to pressurize the cabin.
If cruise altitude is unavailable from the FMC in AUTO, the default cruise altitude is 41,000 feet.
In normal operation of the cruise mode, maximum cabin altitude is no more than 6000 feet.
Which statement is correct regarding bleed air?
Bleed air is supplied by the engines and is used only for hydraulic reservoir pressurization.
Bleed air is supplied by the engines and is used only for cabin pressure.
Bleed air is supplied by the engines and is used only for wing anti-ice.
Bleed air is supplied by the engines and is used only for engine core and inlet cowl anti-ice.
Bleed air is supplied by the engines and is used only for engine core and inlet cowl anti-ice.
Which statement about the Alternate Ventilation System is correct?
The Alternate Ventilation System provides an alternate means of ventilating the cabin and flight deck in the event both packs are inoperative.
When the airplane is not pressurized normally and the ALT VENT switch is ON, air is drawn from the aft outflow valve to the flight deck.
The Alternate Ventilation System provides air flow into the forward electronics bay when both air conditioning packs are off on the ground.
The ALT VENT switch is guarded to prevent selection, which could open the vent valve and depressurize the plane.
The Alternate Ventilation System provides an alternate means of ventilating the cabin and flight deck in the event both packs are inoperative.
The aft equipment cooling system provides cooling and ventilating air for the aft E/E equipment compartment and heating/ventilating air for the aft cargo compartment.
True
False
True
The aircraft is divided into how many temperature zones for air conditioning?
5
7
2
4
7
Two identical air conditioning packs are supplied pressurized air from…
four Cabin Air Compressors (CACs).
the bleed air system.
four Ram Air Fans.
APU bleed air.
four Cabin Air Compressors (CACs).
If one Cabin Air Compressor (CACs) fails its respective air conditioning pack will shut down.
True
False
False
Normally, to maximize system efficiency, only one CAC on each side runs when using __________ as the power source. During cold weather operations both CACs are commanded on.
the APU
PCA
external air
the right engine
the APU
For normal engine starts, how many Cabin Air Compressors (CACs) are commanded off during the initial start sequence?
one on the right side and one on the left.Cabin Air Compressor on the right side
one on the right side
one on the left side
all four
all four
For certain internal malfunctions, pack control automatically uses ___________ as a backup to normal mode.
standby cooling mode
alternate cooling mode
direct cooling mode
secondary cooling mode
standby cooling mode